A group of bikers led by a pub landlord from Yorkshire in northern England has begun night-time patrols of flood-ravaged towns and villages to scare off potential looters following reports of thefts.

"We're big chaps, a lot of us. If people see us they're liable to go away," 57-year-old Lloyd Spencer, head of the Drifters motorcycle club told AFP on Tuesday before setting off for a third night of patrols.

"We saw something on Facebook about looters," he said.

Spencer said he was expecting around 30 bikers to turn out, including some from other clubs Pyratz, Nuntaii Mortis and Broken Bones who have volunteered.

"We get negative press but we're normal blokes, most of us," said Spencer, adding that he and the others would not be on their beloved motorbikes because of the high water -- resorting to cars and vans instead.

Spencer said the police had welcomed the bikers' help and locals had kept them warm with pots of tea and chip butties -- a type of sandwich made up of French fries in a buttered bread roll typical of northern England.

"We're keeping an eye on things. There's loads of people out there but once you get to nighttime there's nobody," said Spencer, who runs a pub called The Northern in the nearby city of Bradford.

One flood-hit town, Hebden Bridge, was "like a warzone" with no street lighting, he said.

"People are just nicking stuff. We've stopped a couple of vans. Once they saw us, they put stuff down."

The bikers also say they have scared off potential burglars at a school and Spencer said they would be holding a fundraising night at his pub on Saturday to buy new Christmas toys for local children.

Spencer said the floods have covered such a wide area that "even we were stretched" for night-time patrols.

West Yorkshire Police said they had received "a handful" of reports that people in vans were "taking dry goods left outside flooded homes".

"The matter was investigated by officers in the area and no evidence was found of vans in situ in the area, or of looting offences taking place. No arrests were made, but to reassure residents patrols were stepped up overnight," a police spokesman said.